Molding machine



April 27, 194s. s. J. MYERS MOLDING MACHINE Filed Aug. 21, y194e; 2 sheets-sheet 1 www April 27, 1948. s, J, MYERS MoLDING MACHINE Filed Aug. 21, 194e 2 Sheets-Sheet 2 f F13. L

Patented Apr. 27, 14948 UNITED MOLDING MACHINE Stuart J. Myers, Warren, Pa., assigner to Warren Plastics Corporation, Warren, Pa., a corporation of Delaware Application August 21, 194,6, Serial No. 692,037

4 Claims. 1

This invention relates to the compression molding of articles from plastic material through the use of an automatic turret type machine. More particularly, the invention pertains to means for heating the molds of such machines during a molding cycle.

In turret type machines for certain continuous sequential molding, each mold is successively lled, closed, heated to a predetermined temperature for a given period; then opened and the molded piece ejected. Each mold, during a molding cycle, is subjected to some form of heat from approximately the time of closing to that of opening. It has been the practice to heat these molds in one of two Ways. Some molding machines have included molds individually fitted with electrical heating elements which, through distributing rings, connected them with a source of current supply. Another method of heating the molds has been to enclose or jacket each mold in a manner to provide a compartment into which steam was admitted from a distributor or manifold. Both of these mold heating mechanisms obviously require each mold unit to be manufactured with either an electrical heating element or a icompartmented jacket. Inasmuch as each mold is formed from two separable elements, it is evident that the carrying units for each of these elements must each be provided with either of the above mentioned heating mechanisms. 30

A considerable problem is always presented in structures of this nature wherein electrical current or steam from a stationary source must be transmitted to a multiplicity of revolving units. Although these methods of heating the molds have served to produce su'icient heat in each mold to effect desired curing of the 4plastic material, it is believed the more or less complicated equipment required subjects the machines so equipped to frequent breakdown, with a resulting time loss, repair cost, and waste of, or damage to, the molded articles.

It is a purpose and object of the present invention to provide means for heating the molds of a turret type automatic molding machine.

Itis another object of the invention to provide heating means of such nature as to be entirely free and independent of the molds carried by the revolvable turret.

Y 2 provide mold heating means in the form of a gas burner manifold thlat conforms to the particular arrangement of the molds, the present disclosure being shown as partially encircling a machine turret and having jets disposed in close proximity with the revolvable molds carried by the turret.

Another and further object of the invention lies in Ithe provision of gas jet heating means in conjunction with gas control valves which are responsive to mold temperature indicating means to the extent .that a desired predetermined heat may be maintained in the molds.

Other objects and advantages of the invention will be more fully understood from a consideration of the following specification, taken in conjunction With the accompanying drawings; and in which Fig. 1 is la front elevational view of a turret form of the invention;

Fig. 2' is a top plan View of the structure shown in' Fig. 1;

Fig. 3 is a greatly enlarged fragmentary vertical vieW (partly in section) oi the molds, showing the location of the mold heating means ;A and Fig. 4 is' an enlarged fragmentary plan View showing the proximity of the heating jets to the molds, being taken substantially as suggested by the line 4-4 of Fig. 3.

Referring more particularly to the drawings, the reference numeral l0 is employed to generally designate a turret type molding machineadapted for continuous sequential operation. The machine illustrated is of the type shown and described in the David Cropp application, Serial No. 604,762,y and includes a reviolvable turret il mounted in any WellV known manner on a center support carried by a base l2. Of course, suitable mechamsm is provided for the purpose'of rotating the turret at any desired constant speed. The turret Il includes Ian upper portion I3 to which is attached a plurality of radially disposed brack ets or mold element supports I4. These supports, in the present disclosure, include portions i6 and I1. The upper element I 8 of each mold is secured to support l1, whereas the lower element I9 is mounted for movement through the support I6 into and out of mold closing position. The par- It is afurther object of the invention to provide 5o ticular mechanism by which the mold elements heating means that, being stationary and independent of the revolvable molds, makes possible the use of relatively simple and inexpensive mold carrying units.

It is still another object are relatively opened land closed forms no part of the present invention and is, therefore, neither shown nor described.

In the present form of the invention the staof the invention to tionary base l2 serves to mount upright supports 2i. At their upper ends these supports have brackets suitable for securing a pair of manifolds or tubes 22 and 23. These manifolds are curved to encircle and be uniformly spaced around the turret, substantially as suggested in Fig. 2 of the drawings. One manifold is mounted in spaced, superposed relation to the other manifold, with manifold 23 in the horizontal plane of mold element I8 and manifold 22 in the hori- Zontal plane of mold element I9, when the mold elements are in the position shown in Fig. 3.

Each manifold includes a multiplicity of radially,

inwardly extending jets 2d. As may be seen in the drawing, the ends of these jets are in close proximity with the outermost portions of the molds. Caps 2% serve to close the ends of the manifolds and, at any suitablepont intermediate these ends, nipples 21 are provided to facilitate connection of the manifolds with a gas supply line 2B. Manifold 22 has connection with line 28 through a pipe 249,A Whereas manifold 23- is connected with the line Edthrough a pipe Sil.A The connecting'pipes 2%- and -30 include Valves 3l and S52; respectively, which are operable to controlow ofgas from the line 2 3 to manifolds 22 and 23 for the purpose of providing for an increase `or decrease of applied heat to either or both sets ofV mold elements. These valves may have means for manualcontrol but, for the purposeofthe invention, arel normallyoperated automatically through thermostatic d-evicesw33 and- 34, which are connected respectively` with the lower and uppersets'of mold elements.

From the foregoing itis-'vevident that heat from the` jets of the stationary-.manifolds is applied to only the frontal. surface of each mold. element as the turret revolves. With a conventionalftype. of mold. element, such application of heat would` be insufficient toe'ect completeY curing of the articles being moldedi Inv practice, that.. portion. of each article remotenfromtheheat would be under cured, and the balance; of the.

article. fully, cur-.edi '1 -o1 assure.y uniform. curing of.v articles.. molded.y in. a` lrlachinevv of `this type. it is. plqmsedltqpro eeachfot the mold elements.v .8` and lil; withN winesfor extensions, ttc. and; |911, rearetvelrf be; seen in, the. drawiria4 these Wines.: are the, fall; thiekn-ess; Qrfheieht of, the element of which they fo an integral part. They extend leteralt freirlfgpeosiie Sides; te an exteiit toeratlyt'ipor-easathe frontal area Orfthe elements. 'Thefvv es, beingv subjected to heaty emanating from th'er'n'anifold jets, serlve to conduct sucient heat to the rear of veach element to effect uniform and complete curing.

To operateaturret type milldine' machine embodying' the heating` means'of. the invention, the thermostats for the upper 'and` lower sets of mold' elements may be adjusted or set to the tempera-r ture at which a given plastic will cure duringa, cycle of operation ofthe machine. 'Ihe jets may then be lightedandv the turret startedrevolving. At such time as the temperature indicatingmeans shows, the elementsjofvthe molds to be heated to the desired temperature, plastic material may be' sequentially fed to thel molds through whatever mechanism may b e provided-on'the machine for this purpose. The flame emanating from eachl jet is 'of suchforce 'as tocause fit tovirtually brush the entire frontalsurface and-both wings ofV each ofA the mold elementswithwh-ich it is aligned. Thus, asthe turretof the machine makes one complete revolution, the moldelementsare subjected toI the heating effectof` successi-ve jets. During-aperiod.y off useit-is Yevident thatf` the molds may tend to heat up to a higher temperature than desired for a given curing. At such time the thermostatic device operates to reduce the flame of gas to either or both of the manifolds 22 and 23, and the lesser flame from the jets will continue until the temperature of the molds has been lowered to an extent to again call for full heat.

From the foregoing it is evident that through use of the present invention, the mold element may be of extremely simple construction and that no means other than that for indicating the temperature of the molds need be attached thereto. lur-thermore,i it is possible to adapt the structure of the'rinvention tothe curing of a large variety of plastics in an automatic turret type machine.

ltlthoughv applicant has shown and described only one form of his invention, it will be apparent to those skilled in the ari-that modification thereof, to the extent of altering the burner structure and adapting it toother turret type machines,

is contemplated insofar as it is within the spirit andA scope of the invention asV set annexed claims.

Having thus setforth my invention, what I claim as new and for which I desire'protection by Letters `Patent is: Y

l'. -Ina'molding machine having a rotatable turret of generally circular cross section, means for rotating said'turret, a plurality of molds carriedby and; radially disposedA in a common planeI about said turretsa-idmolds including upper and of; molds carried by and vdisposed in 'a common, plane about saidturret, saidV molds including upper and lower separable elements, each of said elements having aheat absorbing frontal Aportion consisting of -acentralmoldarea integralwith 0p.

posed extensions, structure'forheating the elements o ffsaidmolds comprisingetwo stationary gas heatingunits; arranged ina-n arc about saldaturret and, including amultiplicity o f iets disposed.

in close proximity withA the frontal portions of,

Said elements, saidfiets, beine so positionedas to plurality of molds carried by andradiallydisposed in a common. plane about, saidi turret, saidimolds including' upper, and lowerfseparabl@ elements,

v each ofisaidlelements'comprisinga central mold arcaand extensions. proj ectingf from .oppositefs'ldes offsaidmolda-rea, and structure for-'heatingsaid moldsV consisting ofA two gas heating 'units ar.

ranged in an arc of the same center as-thatof'saidturret and so positioned: as t0-ldirect Aa: flame-successivelyy onto one. extension, the central moldA area andf the` other extension, of eachy of--said molds.

4. In a molding machine having acircularfrotatable turret, means forrotatingsaidturrete-a out in theA 5 plurality of molds carried by and radially disposed in a common horizontal plane around said turret, each of said molds comprising upper and lower separable elements, each element having a central mold area and a heat absorbing portion partly surrounding said area, wing-like heat absorbing extensions projecting from opposite sides of said element integral with said heat absorbing portion, and structure for heating the elements of said molds consisting of a gas heating device having a plurality of burners so positioned as to direct a ame successively onto one extension, the central mold area, and the other extension, of each of said molds.

STUART J. MYERS.

REFERENCES CITED The following references are of record in the i le of this patent:

UNITED STATES PATENTS 10 Number Name Date 1,356,870 Maeda Oct. 26, 1920 2,058,880 Hunt Oct. 27, 1936 

